<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    div{
      width: 400px;
      height: 400px;
      background: gray;
      border-style: dotted;
      border-width: 10px;
      border-color: red;
    }
  </style>
</head>
<body>
<div>
  你好
</div>
</body>
</html>